The eye of the soil

Soil Chromas

Juergen and I were introduced to an empowering method of soil testing during a Biofertiliser workshop at Milkwood Farm presented by Eugenio Gras from Mexico. A long time advocate of Permaculture and organic farming, Eugenio is involved in Mas Humus (More Humus), an organisation that works with Mexican farmers to build soil fertility. Among other pioneering work, he and his colleagues at Mas Humus have introduced thousands of farmers to soil chromatography which is a cheap (about 3 USD per test), easy, and effective way to access and monitor soil improvement at any time, and as frequently as needed without having to depend on expensive laboratory tests.


soil chroma

So, how does soil chromatography work? What you’re looking at is the end product of a chromatography soil test. It is a chroma profile of a soil specimen. A soil chroma is a visual translation of how well organic matter, minerals and soil organisms are integrated into the process of building soil. Very much like the iris of our eyes, soil chromas that are vibrant, and radiating, tell us that the soil is dynamic and alive. If it is flat and pale, it tells us that the soil is pretty much dead. One could say that soil chromas are windows to the soil’s soul.

chromatography lab

Basic needs for a Chromatography Lab: Translated from its Greek roots chroma and graphein, Chromatography literally means ‘to write with colours’. Through a simple laboratory process that involves breaking down soil specimen in Caustic Soda, and impregnating it into filter paper coated with Silver Nitrate, a radial burst of colours and patterns slowly emerges through capillary and photographic action, telling the story of the presence or the lack of presence of soil building blocks such as Nitrogen & Oxygen, minerals, soil life (macro & micro organisms), humus, and organic matter. Through further interpretation, we are also able to tell if all these building blocks are interacting and effectively functioning  via indicators of enzymatic activity. When compared to standard quantitative soil tests which indicate WHAT minerals and chemicals are present in a soil specimen, chromas are more qualitative in nature, giving insights to HOW the soil is functioning. Both of these tests combined provide a more holistic understanding of a soil specimen.

Eugenio demonstrating the simple laboratory procedures involved


Australian farmers learning how things are done in Mexico


It was indeed mind blowing to see a photographic capture of soil life enfolding through the filter paper in my grasp as I gazed into the eye of the soil, for the first time in my life. I am not surprised to hear that some artists in Mexico are captivated by soil chromas, and have created wall size illustrations of these sun’s on earth.

Eugenio's presentation

Many thanks to Eugenio for the invaluable tool and insights, funny Mexican jokes by the campfire and wonderful company. I have a feeling we shall meet again.

To read more about Eugenio’s workshop check out Milkwood’s article.

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